Managing bioremediation of a creosote-contaminated superfund site by optimizing moisture and temperature in a biopile
Soil moisture content and temperature in a contaminated soil biopile equipped with immobilized microbe bioreactors (IMBRs) were optimized during ex situ bioremediation at a creosotecontaminated Superfund site. Efficiency of remediation during warm summer months without soil-temperature and moisture optimization was compared with that of cold winter months when corrective measures were applied. Significant reduction (35 percent) in total polycyclic aromatic hydrocarbons (PAHs) was observed, compared to 3.97 percent without corrective measures (p<0.05). Kinetic rates (KRs) for total PAH removal were significantly enhanced from 3.93 to 50.95 mg/kg/day. KRs for removal of high molecular mass four-to-six-ring PAHs were also significantly enhanced from 70.29 mg/kg/day to 97.45 mg/kg/day ( p< 0.05). Bioremediation of two- and threering PAHs increased significantly from 15 percent to 40 percent. Benzo[a]pyrene toxicity equivalent mass (BaPequiv ) was significantly reduced by 48 percent with KR of 0.47 mg/kg/day as compared to 22 percent with KR of 0.14 mg/kg/day (p < 0.05). Soil moisture content was enhanced from 15.7 percent to 41.4 percent.